Method of transmitting and receiving ACK/NACK signal and apparatus thereof

ABSTRACT

Disclosed is a method for transmitting an ACK/NACK signal for an HARQ (Hybrid Automatic Repeat reQuest) in a CA (Carrier Aggregation) system, the method including obtaining at least one transmission resource among first and second transmission resources; configuring a first table showing a relationship in which a combination of at least one of the first and second transmission resources and modulation symbols is mapped to an ACK/NACK signal, and transmitting modulation symbols corresponding to a transmission target ACK/NACK signal in the first table by using transmission resource corresponding to the transmission target ACK/NACK signal in the first table.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/826,013, filed on Mar. 20, 2020, which is a continuation of U.S.patent application Ser. No. 16/392,323, filed on Apr. 23, 2019, which isa continuation of U.S. patent application Ser. No. 15/821,238, filed onNov. 22, 2017, which is a continuation of U.S. patent application Ser.No. 15/335,679, filed on Oct. 27, 2016, now issued as U.S. Pat. No.9,860,046, which is a continuation of U.S. patent application Ser. No.14/992,186, filed on Jan. 11, 2016, now issued as U.S. Pat. No.9,485,072, which is a continuation of U.S. patent application Ser. No.13/877,827, filed on Apr. 4, 2013, now issued as U.S. Pat. No.9,237,566, which is the National Stage Entry of InternationalApplication No. PCT/KR2011/007659, filed on Oct. 14, 2011, and claimspriority to and the benefit of Korean Patent Application No.10-2010-0100988, filed on Oct. 15, 2010, all of which are herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

The present invention relates to wireless communication and, moreparticularly, to a wireless communication system supporting multiplecarriers.

Discussion of the Background

A wireless communication system generally uses a single bandwidth fordata transmission, and respective mobile communication generation usedifferent bandwidths. For example, a 2^(nd)-generation wirelesscommunication system uses a bandwidth of 200 KHz to 1.25 MHz, a3^(rd)-wireless communication system uses a bandwidth of 5 MHz to 10MHz. In order to support an increasing transmission capacity, recently,LTE (Long Term Evolution) or IEEE 802.16m continue to extend theirbandwidth to 20 MHz or even higher. It may be requisite to increase thebandwidth to enhance transmission capacity, but it is not easy toallocate frequency of a large bandwidth, except for some areas globally.

A carrier aggregation (CA) technique for binding (or grouping) aplurality of physically non-continuous bands in a frequency domain toobtain an effect of using a logically large band has been developed inorder to effectively use fragmented small bands. Individual unitcarriers bound through carrier aggregation are called component carriers(CCs). Each of the component carriers (CCs) is defined by a singlebandwidth and central frequency.

A system for transmitting and/or receiving data in a broadband through aplurality of component carriers is called a CA (Carrier Aggregation)system or a carrier aggregation environment. The CA system supports botha narrowband and a broadband by using one or more carriers. For example,when one carrier corresponds to a bandwidth of 5 MHz, a bandwidth of amaximum of 20 MHz is supported by using four carriers.

In order to operate the CA system, various control signaling is requiredbetween a base station (BS) and a user equipment (UE). For example,exchanging of ACK (ACKnowledgement)/NACK (Not-ACKnowledgement)information to perform HARQ (Hybrid Automatic Repeat reQuest),exchanging of CQI (Channel Quality Indicator) indicating downlinkchannel quality, and the like, are required.

In this connection, however, since a plurality of uplink CCs and aplurality of downlink CCs are used in the multi-CC system, an apparatusand method for exchanging various control signaling between a BS and aUE in such a communication environment are required.

SUMMARY

Therefore, an object of the present invention is to provide an apparatusand method for effectively allocating transmission resources fortransmitting an ACK/NACK signal with respect to a plurality of componentcarriers (CCs) in a CA system.

Another object of the present invention is to provide an apparatus andmethod for effectively using radio resources by using resourcesallocated for repeatedly transferred control signals in a CA system.

Another object of the present invention is to provide a resourceallocation method for preventing a collision of radio resources andsmoothly performing communication in a CA system.

According to an aspect of the present invention, there is provided amethod for transmitting an ACK/NACK signal for an HARQ (Hybrid AutomaticRepeat reQuest) in a CA system, including: obtaining at least onetransmission resource through a resource allocation indicatortransmitted on a downlink control channel; and obtaining at least onesecond transmission resource based on at least one of resources used forthe downlink control channel, wherein the transmission of the ACK/NACKsignal is performed through a transmission and a modulation symbolmapped by a first table comprised of combinations of the obtained firstand/or second transmission resources and modulation symbols of theACK/NACK signal.

The number of first and/or second transmission resources may beallocated according to the number of transmission bits of the ACK/NACKsignal.

The resource allocation indicator may be transferred by using resourceallocated to control information repeatedly transmitted through aplurality of CCs.

The first transmission resource may be a transmission resource mapped bya resource allocation indicator on a second table comprised of a certaintransmission resource group.

The transmission of the ACK/NACK signal may be performed through amulti-antenna system, and the method may further include obtaining athird transmission resource different from the first and secondtransmission resources, wherein a transmission resource mapped in thefirst table may be allocated to a first antenna, a third transmissionresource may be allocated to a second antenna, and modulation symbolsmapped in the first table may be transmitted through the first andsecond antennas.

According to another aspect of the present invention, there is provideda method for receiving an ACK/NACK signal for an HARQ (Hybrid AutomaticRepeat reQuest) in a CA system, including: allocating at least one firsttransmission resource to be used for transmission of an uplink ACK/NACKsignal through a resource allocation indicator transmitted on a downlinkcontrol channel; and transmitting a resource allocation indicator on adownlink control channel, wherein the resource allocation indicator mayindicate a transmission resource to be used for transmission of theACK/NACK signal in a table comprised of a certain transmission resourcegroup.

The resource allocation indicator may be transferred by using resourceallocated to control information repeatedly transmitted through aplurality of CCs.

According to another aspect of the present invention, there is providedan apparatus for transmitting an ACK/NACK signal for an HARQ (HybridAutomatic Repeat reQuest) in a CA system, including: an RF unitreceiving a downlink transport block through a downlink allocationindicated by a downlink control channel and transmitting an ACK/NACKsignal with respect to the downlink transport block; and a signalprocessing unit processing a signal received from the RF unit and asignal transmitted via the RF unit, wherein the signal processing unitobtains at least one first transmission resource through a resourceallocation indicator transmitted on the downlink control channel,obtains at least one second transmission resource based on at least oneof resources used for the downlink control channel, and maps modulationsymbols and a transmission resource to be used for transmission of theACK/NACK in a table comprised of combinations of first and/or secondtransmission resources and modulation symbols of ACK/NACK transmission,and the RF unit transmits an ACK/NACK signal by using the mappedtransmission resource and modulation symbols.

The RF unit may include a plurality of antennas, a transmission resourcemapped in the table may be allocated to a first antenna among theplurality of antennas, a transmission resource different from the firstand second transmission resources may be allocated to a second antennaamong the plurality of antennas, and symbols mapped in the table may betransmitted through the first and second antennas.

According to another aspect of the present invention, there is providedan apparatus for receiving an ACK/NACK signal for an HARQ (HybridAutomatic Repeat reQuest) in a CA system, including: an RF unittransmitting a downlink transport block through a downlink allocationindicated by a downlink control channel and receiving an ACK/NACK signalwith respect to the downlink transport block; and a signal processingunit processing a signal transmitted from the RF unit and a signalreceived through the RF unit, wherein the signal processing unitallocates at least one transmission resource to be used for transmissionof an ACK/NACK signal through a resource allocation indicatortransmitted on the downlink control channel, the RF unit transmits aresource allocation indicator on the downlink control channel, and theresource allocation indicator indicates a transmission resource to beused for transmission of the ACK/NACK signal in a table comprised of acertain transmission resource group.

According to another aspect of the present invention, there is provideda method for transmitting an ACK/NACK signal for an HARQ (HybridAutomatic Repeat reQuest) by a user equipment (UE) in a CA system,including: obtaining at least one transmission resource among first andsecond transmission resources; and transmitting modulation symbolscorresponding to a transmission target ACK/NACK signal in a first table,which shows a relationship in which a combination of at least one of thefirst and second transmission resources and modulation symbols is mappedto an ACK/NACK signal, by using n_(PUCCH) ⁽¹⁾ corresponding to thetransmission target ACK/NACK signal in the first table, wherein thefirst transmission resource is indicated by a control element used for afirst downlink control channel, the second transmission resource is atleast one transmission resource among sets of transmission resources ina second table indicated by a resource allocation indicator transmittedon a second downlink control channel, and the second table may show acorrespondence relationship between indication values of the resourceallocation indicators and sets of transmission resources transmitted tothe UE through higher layer signaling.

The number of first and/or second transmission resources may beallocated according to the number of transmission bits of the ACK/NACKsignal, and the resource allocation indicator may be transferred byusing resource allocated to control information repeatedly transmittedthrough a plurality of CCs.

The sets of transmission resources may include transmission resourcescorresponding to the number of transport blocks transmitted on a datachannel indicated by a control signal transmitted on the second downlinkcontrol channel.

The second transmission resource may be allocated according to thenumber of transport blocks transmitted on the data channel indicated bythe control signal transmitted on the second downlink control channel.

The resource allocation indicator may be comprised of N-bit information,the second table may be comprised of 2^(N) number of resource groups,the resource groups may be comprised of the resource sets or elements ofthe resource sets, and the resource groups may be comprised of the samenumber of transmission resources as that of transport blocks transmittedon the data channel indicated by the second downlink control channel.

The method may further include: obtaining a third transmission resourcedifferent from the first and second transmission resources, wherein atransmission resource mapped in the first table may be allocated to afirst antenna, a third transmission resource may be allocated to asecond antenna, and modulation symbols mapped to the ACK/NACK signal inthe first table may be transmitted through the first and secondantennas.

According to another aspect of the present invention, there is provideda method for receiving an ACK/NACK signal for an HARQ (Hybrid AutomaticRepeat reQuest) in a CA system, including: allocating at least onetransmission resource to be used for reception of an uplink ACK/NACKsignal through a resource allocation indicator transmitted on a downlinkcontrol channel; and transmitting a resource allocation indicator on adownlink control channel, wherein the resource allocation indicator mayindicate at least one transmission resource in a resource allocationtable, and the resource allocation table may show a correspondencerelationship between indication values of the resource allocationindicators and sets of transmission resources transmitted to the UEthrough higher layer signaling.

The resource allocation indicator may be transferred by using resourceallocated to control information repeatedly transmitted through aplurality of CCs, and may be comprised of N-bit information. When theresource allocation indicator is comprised of N-bit information, theresource allocation table may be comprised of 2^(N) number of resourcegroups, and the resource groups may be comprised of resource sets orelements of the resource sets.

The resource groups may be comprised of the same number of transmissionresources as that of transport blocks transmitted on the data channelindicated by the downlink control channel.

According to another aspect of the present invention, there is providedan apparatus for transmitting an ACK/NACK signal for an HARQ (HybridAutomatic Repeat reQuest) in a CA system, including: an RF unitreceiving a downlink transport block through a downlink allocationindicated by a downlink control channel and transmitting an ACK/NACKsignal with respect to the downlink transport block; and a signalprocessing unit processing a signal received from the RF unit and asignal transmitted via the RF unit, wherein the signal processing unitobtains at least one of first and second transmission resources anddetermines transmission symbols and transmission resource mapped to theACK/NACK signal to be transmitted, and the RF unit transmits thetransmission symbols by using the transmission resource, thetransmission symbols and the transmission resource are determinedcorrespondingly according to an ACK/NACK to be transmitted in a firsttable, which shows a relationship in which a combination of at least oneof the first and second transmission resources and modulation symbols ismapped to an ACK/NACK signal, the first transmission resource isindicated by a control element used for a first downlink controlchannel, the second transmission resource is at least one transmissionresource among sets of transmission resources in a second tableindicated by a resource allocation indicator transmitted on a seconddownlink control channel, and the second table may show a correspondencerelationship between indication values of the resource allocationindicators and sets of transmission resources configured based ontransmission resources transmitted to the UE through higher layersignaling.

The resource allocation indicator may be comprised of N-bit information,the second table may be comprised of 2^(N) number of resource groups,and the resource groups may be comprised of the resource sets orelements of the resource sets.

According to another aspect of the present invention, there is providedan apparatus for receiving an ACK/NACK signal for an HARQ (HybridAutomatic Repeat reQuest) in a CA system, including: an RF unittransmitting a downlink transport block through a downlink allocationindicated by a downlink control channel and receiving an ACK/NACK signalwith respect to the downlink transport block; and a signal processingunit processing a signal transmitted from the RF unit and a signalreceived via the RF unit, wherein the signal processing unit allocatesat least one transmission resource to be used for transmission of anACK/NACK signal through a resource allocation indicator transmitted onthe downlink control channel, the RF unit transmits a resourceallocation indicator on the downlink control channel, the resourceallocation indicator indicates at last one transmission resource in aresource transmission table, and the resource allocation table shows acorrespondence relationship between indication values of the resourceallocation indicators and sets of transmission resources transmitted toa user equipment (UE) through higher layer signaling.

The number of transmission resources mapped to the value of the resourceallocation indicator may correspond to the number of transport blockstransmitted on a data channel indicated by the downlink control channel.

According to an embodiment of the present invention, in a CA system,transmission resources for transmitting an ACK/NACK signal with respectto a plurality of component carriers can be effectively allocated.

According to an embodiment of the present invention, in a CA system,radio resources can be effectively used by using resource allocated torepeatedly transferred control signals.

According to an embodiment of the present invention, in a CA system, acollision of radio resources can be prevented and smooth communicationcan be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view for schematically explaining a downlink HARQand CQI transmission.

FIG. 2 is a view for schematically explaining a method for transmittingdownlink control information in a CA system.

FIG. 3 is a view schematically showing a transmission and receptionrelationship between a base station and a user equipment in the CAsystem.

FIG. 4 is a view schematically explaining using resource allocated torepeated TPC (Transmission Power Control) fields in the CA system.

FIG. 5 is a flow chart illustrating the process of a method fortransmitting an ACK/NACK signal by a user equipment in a multi-antennasystem.

FIG. 6 is a schematic block diagram showing an example of an apparatusfor transmitting an HARQ ACK/NACK signal in the multi-antenna system.

FIG. 7 is a schematic block diagram of a wireless communication systemimplemented by an embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Embodiments of the present invention will now be described in detailwith reference to the accompanying drawings. It should be understoodthat, in applying reference numerals to constituents of each drawing,although the same constituents are shown on different drawings, they aredenoted by the same reference numbers as possible. In describing thepresent invention, if a detailed explanation for a related knownfunction or construction is considered to unnecessarily divert the gistof the present invention, such explanation will be omitted but would beunderstood by those skilled in the art.

In describing the elements of the present invention, terms such asfirst, second, A, B, (a), (b), etc., may be used. Such terms are usedfor merely discriminating the corresponding elements from other elementsand the corresponding elements are not limited in their essence,sequence, or precedence by the terms. It will be understood that when anelement or layer is referred to as being “on” or “connected to” anotherelement or layer, it can be directly on or directly connected to theother element or layer, or intervening elements or layers may bepresent.

In the present disclosure, a wireless communication network will bedescribed, and an operation performed in the wireless communicationnetwork may be performed in a process of controlling a network andtransmitting data by a system (e.g., a base station (BS)) administeringthe corresponding wireless communication network or may be performed ina mobile station (MS) connected to the corresponding wireless network.

A wireless communication system is widely disposed to provide variouscommunication services such as voice and packet data, or the like. Thewireless communication system includes at least one base station (BS). ABS generally refers to a fixed station that communicates with a mobilestation (MS) and may be called by other names such as evolved-node B(eNB), base transceiver system (BTS), access point (AP), etc. Each BSprovides a communication service to particular geographical areas (whichare generally called cells). Cells may be construed to havecomprehensive meanings indicating partial areas covered by a BS, and mayinclude various coverage areas such as a mega-cell, a macro-cell, amicro-cell, a pico-cell, a femto-cell, and the like.

A mobile station (MS) may be fixed or mobile and may be referred to byother names such as user equipment (UE), mobile terminal (MT), userterminal (UT), subscriber station (SS), wireless device, personaldigital assistant (PDA), wireless modem, handheld device, etc.

Multi-access schemes applied to the wireless communication system arenot limited. Namely, various multi-access schemes such as CDMA CodeDivision Multiple Access), TDMA (Time Division Multiple Access), FDMA(Frequency Division Multiple Access), OFDMA (Orthogonal FrequencyDivision Multiple Access), SC-FDMA (Single Carrier-FDMA), OFDM-FDMA,OFDM-TDMA, OFDM-CDMA, or the like, may be used. A TDD (Time DivisionDuplex) scheme in which transmission is made by using a different timeor an FDD (Frequency Division Duplex) scheme in which transmission ismade by using different frequencies may be applied to an uplinktransmission or a downlink transmission.

A carrier aggregation (CA) supports a plurality of carriers, which isalso called a spectrum aggregation or a bandwidth aggregation.

Sizes (i.e., bandwidths) of component carriers constituting a CA mayvary.

Hereinafter, a multi-carrier system refers to a system supporting thecarrier aggregation.

Component carriers may be divided into a primary component carrier and asecondary component carrier depending on whether or not they areactivated. The primary component carrier is a carrier which is activatedall the time, and the secondary carrier is a carrier which is activatedor deactivated according to particular conditions. Here, activationrefers to a state in which traffic data is transmitted or received or astate in which traffic data is ready to be transmitted or received.Deactivation refers to a state in which traffic data cannot betransmitted or received and measurement or transmission or reception ofminimum information is available. A UE may use only one primarycomponent carrier or one or more secondary component carriers along witha primary component carrier.

FIG. 1 shows a downlink HARQ and CQI transmission.

With reference to FIG. 1 , when a UE receives downlink data from a BS,it transmits ACK (ACKnowledgement)/NACK (Not-ACKnowledgement)information after the lapse of a certain time. The downlink data may betransmitted on a PDSCH indicated by a PDCCH. The ACK/NACK signal may beACK information when the downlink data is successfully decoded, and maybe NACK information when the downlink data fails to be decoded. When theNACK information received, the BS may retransmit the downlink data up toa maximum retransmission number.

A transmission time of the ACK/NACK signal with respect to the downlinkdata or a resource allocation may be dynamically informed by the BS, ormay be previously agreed according to a transmission time of thedownlink data or a resource allocation.

The UE may measure a downlink channel state and report a CQI to the BSperiodically and/or aperiodically. The BS may inform the UE about atransmission time of the CQI or a resource allocation.

Meanwhile, the PUCCH may support multiple formats. Namely, it maytransmit uplink control information having different number of bits persubframe according to a modulation scheme and a PUCH transmissionformat. Table 1 below shows modulation schemes and number of bitsaccording to various PUCCH formats.

TABLE 1 Number of bits per PUCCH format Modulation scheme subframe 1 N/A N/A 1a BPSK 1 1b QPSK 2 2  QPSK 20 2a QPSK + BPSK 21 2b QPSK + QPSK22 3  QPSK 48

PUCCH format 1 may be used for transmitting a scheduling request (SR).PUCCH format 1a/1b may be used for transmitting an HARQ ACK/NACK signal.PUCCH format 2 may be used for transmitting a CQI, and PUCCH format2a/2b may be used for transmitting HARQ ACK/NACK. When the HARQ ACK/NACKsignal is transmitted alone, PUCCH format 1a/1b/3 may be used, and whenSR is transmitted alone, PUCCH format 1 may be used.

Resource index n⁽¹⁾PUCCH, resource for transmission of PUCCH format1/1a/1b is used to determine the amount of CS α(n_(s),1) of a basicsequence and an orthogonal sequence index n_(OC)(n_(s)), as well as theposition of a physical resource block in which the ACK/NACK signal istransmitted. The resource index n⁽¹⁾ _(PUCCH) for the HARQ ACK/NACK maybe obtained as shown in Table 2 below. The resource index n⁽¹⁾ _(PUCCH)may be used as a parameter for determining a physical RB index n_(PRB),the amount of CS α(n_(s),1) of the basic sequence, the orthogonalsequence index n_(OC)(n_(s)), and the like.

TABLE 2 Dynamic scheduling Semi-persistent scheduling Resource indexn⁽¹⁾ _(PUCCH) = n_(CCE) + Signaled by higher layer N⁽¹⁾ _(PUCCH) or acontrol channel Higher Layer N⁽¹⁾ _(PUCCH) n⁽¹⁾ _(PUCCH) Signaling value

Namely, the HARQ ACK/NACK signal with respect to the PDCCH transmittedat an nth subframe is transmitted at a (n+4)th subframe by usingresource index n⁽¹⁾ _(PUCCH), the sum of a first CCE (Control ChannelElement) index n_(CCE) of the PDCCH transmitted in the nth subframe andthe value n⁽¹⁾ _(PUCCH) obtained through higher layer signaling or aseparate control channel. For example, n⁽¹⁾ _(PUCCH) may be a totalnumber of PUCCH format 1/1a/1b resources required for semi-persistentscheduling (SPS) transmission and service request (SR) transmission. Asfor the semi-persistent scheduling (SPS) transmission and servicerequest (SR) transmission, since there is no PDCCH indicating thecorresponding PDSCH transmission, the BS may explicitly inform the UEabout n⁽¹⁾ _(PUCCH).

When the HARQ ACK/NACK signal and/or the SR are transmitted throughPUCCH format 1/1a/1b, the physical RB index n_(PRB) is determined by theresource index n⁽¹⁾ _(PUCCH). This is shown as expressed by Equation 1below.

                                   Math  FIG.  1$m = \left\{ {{\begin{matrix}N_{RB}^{(2)} & {{{if}\mspace{14mu} n_{PUCCH}^{(1)}} < {c \cdot {N_{cs}^{(1)}/\Delta_{shift}^{PUCCH}}}} \\{\left\lfloor \frac{\begin{matrix}{n_{PUCCH}^{(1)} - {c \cdot}} \\{N_{cs}^{(1)}/\Delta_{shift}^{PUCCH}}\end{matrix}}{c \cdot {N_{sc}^{RB}/\Delta_{shift}^{PUCCH}}} \right\rfloor + N_{RB}^{(2)} + \left\lceil \frac{N_{cs}^{(1)}}{8} \right\rceil} & {otherwise}\end{matrix}\mspace{20mu} c} = \left\{ {{\begin{matrix}3 & {{normal}\mspace{14mu}{cyclic}\mspace{14mu}{prefix}} \\2 & {{extended}\mspace{14mu}{cyclic}\mspace{14mu}{prefix}}\end{matrix}\mspace{20mu} n_{PRB}} = \left\{ \begin{matrix}\left\lfloor \frac{m}{2} \right\rfloor & {{{if}\mspace{14mu}\left( {m + {n_{s}{mod}\; 2}} \right){mod}\; 2} = 0} \\{N_{RB}^{UL} - 1 - \left\lfloor \frac{m}{2} \right\rfloor} & {{{if}\mspace{14mu}\left( {m + {n_{s}{mod}\; 2}} \right){mod}\; 2} = 1}\end{matrix} \right.} \right.} \right.$

PUCCH format 3 is a PUCCH format employing DFT-S-OFDM (Discrete FourierTransform—Spreading—Orthogonal Frequency-Division Multiplexing), whichuses DFT-IFFT and block-spreading. When the HARQ ACK/NACK signal istransmitted by using PUCCH format 3, information of up to maximum 10bits in case of FDD and information of up to maximum 20 bits may betransmitted in the HARQ ACK/NACK signal by using one ACK/NACK resource.

Meanwhile, when the ACK/NACK signal is transmitted through the PUCCH byusing multiple antennas in uplink, diversity can be obtained bytransmitting the same ACK/NACK symbols through different resources byusing different resources. In this case, however, since the sameACK/NACK signal is transmitted through different antennas, differentACK/NACK transmission resources should be allocated to the respectiveantennas in order to prevent a collision of resources.

For example, an ACK/NACK transmission resource may be allocated to afirst antenna according to a signal transmission table, and an ACK/NACKtransmission resource may be allocated to a second antenna from aresource domain not designated by the signal transmission table totransmit the same ACK/NACK signal through the different antennas,thereby preventing a collision of resources and obtaining transmissiondiversity.

In a carrier aggregation environment, the HARQ ACK/NACK signal may betransmitted through PUCCH format 1/1a/1b using the signal transmissiontable. The signal transmission table is a table for mapping a message tobe transmitted, resource to be used for transmitting the correspondingmessage and modulation symbols. The signal transmission table may beconfigured in various manners. For example, the signal transmissiontable may be comprised of combinations of a plurality of resourceindexes and modulation symbols of an ACK/NACK signal, may be implementeddifferently according to the number (M) of bits used for transmitting anACK/NACK signal, or may be configured as a single table including thenumber (M) of every bit. Thus, when a signal transmission table is usedwith respect to ACK/NACK information having 4 bits or smaller in thecarrier aggregation environment, the signal transmission table may beconfigured when the M values are 2, 3, and 4, and utilized for anACK/NACK transmission resource allocation. An example of the method forallocating transmission resources and mapping transmission resources andmodulation symbols by using the signal transmission table is channelselection. In the following description, channel selection will be takenas an example of a method of using the signal transmission tableaccording to an embodiment of the present invention for the sake ofbrevity.

The format of a table used for channel selection (referred to as a‘channel selection table’, hereinafter) may be transferred to the UE andthe BS in advance by higher layer signaling or may be a table alreadyowned by the UE and the BS. The UE may obtain resource indexes forconfiguring the channel selection table through separate signaling, atransport channel, or the like, from a higher channel.

In order to allocate resource for transmitting the ACK/NACK signal inthe PUCCH format 1/1a/1b using channel selection, the BS may allocateresource indexes according to an implicit resource allocation scheme.The implicit allocating of a resource index by the BS refers toallocating a calculated resource index by using n_(CCE) indicating thenumber of a CCE, among the at least one CCE constituting the PDCCH of CC#a, as a parameter.

The BS may allocate resource indexes according to an explicit resourceallocation scheme. The explicit allocating of resource indexes by the BSrefers to allocating a resource index of a PUCCH dedicated to aparticular UE to the UE through a separate resource allocationindicator, or the like, without relying on n_(CCE). Here, the separateresource allocation indicator includes signaling, or the like, from anupper layer or a physical layer. Also, the resource allocation indicatormay be included as control information or system information in thePDCCH.

In order to explicitly allocate a resource index, the BS may utilize anindicator used for transferring different control information, as aresource allocation indicator. For example, the BS may utilize a powerindicator (PI) with respect to uplink transmission power, as a resourceallocation indicator.

The PI is an indicator for controlling and adjusting uplink transmissionpower. In general, a DCI format indicating a downlink grant includes2-bit PI field for controlling power with respect to the PUCCH, and aDCI format indicating an uplink grant includes 2-bit PI field forcontrolling power with respect to the PUSCH. One example of the PI maybe a transmission power control (TPC). Hereinafter, for content relatedto the PI in an embodiment of the present invention, the TPC will bedescribed as an example for the sake of brevity.

When cross-carrier scheduling is applied in the carrier aggregationenvironment, downlink grants regarding one or more target controlcarriers (i.e., carriers to be controlled) may be transmitted throughcontrol carriers. The control carriers may be carriers transmitting thePDCCH indicating the PDSCH of the target control carriers incross-carrier scheduling, which may be primary component carriers (CC)or secondary component carriers. The target control carriers may becarriers whose PDSCH is indicated by the PDCCH of control carriers,which may be secondary CCs. All of the downlink grants transmit a TPCwith respect to the PUCCH of the uplink CCs linked to the controlcarriers. In this case, one or more of the same TPCs for controllingpower of the same uplink PUCCH are transmitted. These act as overhead ofthe downlink control information resultantly. Thus, when a plurality ofTPCs with respect to one PUCCH exist due to transmission of a pluralityof downlink grants, the bits allocated to the repeated TPC fields may bediverted to be used for transmitting different control information toeffectively use the limited radio resource.

FIG. 2 is a view for schematically explaining a method for transmittingdownlink control information and cross-carrier scheduling in a CAsystem.

In the example of FIG. 2 , the multi-CC system provides three CCs, i.e.,CC1, CC2, and CC3 through carrier aggregation (CA) to the UE. Amongthem, one may be a primary CC and the others may be secondary CCs. It isassumed that CC1 is a primary CC for the sake of brevity.

A downlink subframe of each CC may include a control region including aPDCCH and a data region including a PDSCH. For example, CC1 includes adata region 1070 and a control region 1040, CC2 includes a data region1080 and a control region 1050, and CC3 includes a data region 1090 anda control region 1060.

When CC1, CC2, and CC3 are operated according to cross-carrierscheduling, CC1 may include PDCCHs regarding the PDSCHs 1020 and 1030 ofcarriers CC2 and CC3, as well as a PDCCH with respect to its PDSCH 1010.For example, the control region 1040 of CC1 may include PDCCH1 1001 withrespect to the PDSCH of CC1, PDCCH2 1002 with respect to the PDSCH ofCC2, and PDCCH 3 1003 with respect to the PDSCH of CC3.

Control information transmitted through the PDCCH is called downlinkcontrol information (DCI). A usage purpose of the DCI is differentaccording to its format and a field defined in the DCI is different. TheDCI includes uplink resource allocation information and downlinkresource allocation information. The uplink resource allocationinformation may be called an uplink grant and the downlink resourceallocation information may be called a downlink grant. For example, DCIformat 0 may indicate uplink resource allocation information, and DCIformats 1 to 2C may downlink resource allocation information, and DCIformats 3 and 3A may indicate an uplink TPC (Transmit Power Control)command with respect to certain UE groups. Respective fields of a DCImay be sequentially mapped to information bits. PDCCH1 1001 with respectto the PDSCH of CC1, PDCCH2 1002 with respect to the PDSCH of CC2, andPDCCH3 1003 with respect to the PDSCH of CC3 may transmit a DCI of anyone format among DCI 1/1A/1B/1C/1D/2/2A/2B/2C. A resource allocationfield included in the DCI may indicate a PDSCH of a particular CC. Forexample, the DCI of the PDCCH1 1001 may indicate the PDSCH1 1010, theDCI of the PDCCH2 1002 may indicate the PDSCH2 1020, and the DCI ofPDCCH3 1003 may indicate the PDSCH3 1030.

In this manner, in the carrier aggregation, the DCI information of thePDCCH may transmit resource allocation information with respect to adifferent carrier, as well as resource allocation within the carrier towhich the corresponding PDCCH belongs. This is called cross-carrierscheduling. According to the cross-carrier scheduling, controlinformation regarding a secondary CC can be transmitted through aprimary CC, so scheduling becomes flexible.

Meanwhile, the DCI may further include various fields besides theresource allocation field. For example, the respective DCIs may includea transmission field TPC.

The UE may monitor a plurality of PDCCHs transmitted in the CAenvironment. For example, the UE may monitor the plurality of PDCCHs ina blind decoding manner by using a particular RNTI (Radio NetworkTemporary Identifier) allocated to the UE itself, and extract atransmission field.

FIG. 3 is a view schematically showing a transmission and receptionrelationship between a BS 1120 and a UE 1110 in the CA system.

The BS 1120 aggregates three CCs of CC1 1130, CC2 1140, and CC3 1150,and transmits the same to the UE 1110.

Required information is included in the respective CCs CC1 1130, CC21140, and CC3 1150 and transferred on the PDCCH and the PDSCH,respectively (S1110, S1120, and S1130). Here, the PDCCHs of therespective CCs CC1 1130, CC2 1140, and CC3 1150 include a TPC forcontrolling uplink power.

Upon receiving the respective CCs CC1 1130, CC2 1140, and CC3 1150, theUE 1110 transfers required information on a PUCCH to the BS 1120 inresponse (S1140). The PUCCH includes an HARQ ACK/NACK signal withrespect to whether or not the PDSCHs of the respective CCs CC1 1130, CC21140, and CC3 1150 have been received without an error.

When one PUCCH is transmitted to the BS with respect to a downlinktransmission, as described above, the repeated information of the powerindicators TPC1, TPC2, and TPC3 with respect to the same PUCCH may beincluded and transmitted on the PDCCH of the respective CCs CC1, CC2,and CC3 to the UE. Thus, a method for utilizing the bits allocated tothe repeatedly transmitted TPC fields with respect to the same PUCCH inorder to transmit different control information may be considered.

In FIG. 3 , when CC1 is a primary CC (PCC) and CC2 and CC3 are secondaryCCs (SCC1 and SCC2), the TCP field included in the PDCCH of the PCC maybe used to transfer information for controlling uplink PUCCH power andbits allocated to the TPC fields included in the PDCCHs of SCC1 and SCC2may be used to transfer different control information.

For example, resource may be allocated by using two bits allocated tothe TCP fields included in the PDCCHs of the SCC1 and/or SCC2 to obtainresources constituting a channel selection table for transmitting 2-4bit ACK/NACK signal through the PUCCH.

FIG. 4 is a view schematically explaining using resource allocated tothe repeated TPC fields in the CA system.

In the CA environment, in order to allocate resource to be used for anuplink signal transmission, the BS configures a resource allocationindicator (S1210). For example, an ACK/NACK resource indicator (ARI) maybe configured for an uplink HARQ ACK/NACK signal. The ARI is anindicator explicitly allocating PUCCH resource(s) to be used for the UEto transmit the HARQ ACK/NACK signal. In the following description, theARI will be taken as an example of the PUCCH resource allocationindicator according to the present embodiment.

The BS transmits required information on the PDCCH and the PDSCH to theUE through CCs (S1220). When a plurality of CCs are transmitted, e.g.,when SCCs are transmitted together with a PCC in the multi-CC system,the TPC fields included in the PDCCHs of the SCCs are repeated with theTPC with respect to the PUCCH included in the PDCCH of the PCC. The BSmay transmit the ARI by using the bits allocated to the repeated TPCfields on the SCCs.

The UE checks the PDCCHs of the CCs received from the BS, and isallocated resource from the ARI transmitted by using the bits allocatedto the TPC fields on the SCCs according to the explicit resourceallocation method (S1230).

The UE may configure a channel selection with the transmission resourceobtained through the ARI and the implicitly allocated transmissionresource (to be described) (S1240).

The UE maps PUCCH resource to be used for HARQ ACK/NACK transmission andmodulated symbols according to HARQ ACK/NACK information received by UEin the channel selection table (S1250). Mapping in the channel selectiontable may be simply matching transmission resource to be used fortransmission with respect to a message/signal to be transmitted and/ormatching resource to be used for the transmission and symbols accordingto a type of a message and/or a signal to be transmitted. For example,in case of transmission of the HARQ ACK/NACK signal, transmissionresource to be used for the transmission and symbols to be transmittedmay be mapped.

The UE may transmit symbols and/or a message on the PUCCH by using thetransmission resource determined through mapping in the channelselection table (S1260).

In general, ACK/NACK information regarding PDSCH of a plurality ofdownlink CCs are transmitted through a single UL PCC, e.g., a singlePUCCH. Thus, when a plurality of CCs are used for downlink transmission,as mentioned above, the TPC fields with respect to the PUCCH of thePDCCHs of the respective CCs are repeated.

In particular, when an HARQ ACK/NACK signal with respect to the PDSCHstransferred according to the PUCCH format 1b using channel selection inthe CA environment, namely, transferred by downlink SCCs has 1 to 4bits, 2-bit TPC field within the PDCCHs is diverted to be used toconfigure a channel selection table for transmitting the uplink HARQACK/NACK signal.

Hereinafter, the exclusive use of the 2-bit TPC field within the PDCCHsto configure a channel selection table for transmitting the uplink HARQACK/NACK signal when the HARQ ACK/NACK signal with respect to the PDSCHstransferred via downlink SCCs has 1 to 4 bits according to an embodimentto which the technical concept of the present invention is applied willbe described. Here, a case in which a plurality of CCs are transmittedfrom the BS to the UE in order to divert the 2-bit TPC field to be usedfor an ARI (ACK/NACK Resource Indicator) will be considered.

For the sake of brevity, the case in which the 2-bit TPC field isdiverted to be used to transmit the ARI and a channel selection table isconfigured by using the 2-bit TPC field will be described, but thetechnical concept of the present invention is not limited thereto.

An ARI resource mapping table for allocating resource to the ARI may betransmitted in advance to the UE through higher layer signaling. The ARIresource mapping table is comprised of values of the ARI and HARQACK/NACK transmission resources allocated according to the ARI values.The number of ACK/NACK transmission resources required for configuringthe ARI resource mapping table is determined by the number of SCCsconfigured through an RRC and a transmission mode. Here, thetransmission mode is related to whether to transmit one transport blockfor each CC or whether to transmit two transport blocks for each CCwithin the subframe, but the present invention is not limited thereto,and the transmission mode may reflect various transmission formats, andthe ACK/NACK transmission resource may be determined by varioustransmission modes. Here, the transport block is also called a codeword.

As described above, the ARI resource mapping table is differentlyconfigured according to the number of ACK/NACK transmission resources.The ARI resource mapping table may be previously transferred to the UEthrough higher layer signaling. In the PUCCH format 1b using channelselection in the CA environment, as for ACK/NACK transmission resourcesrequired for transmitting an ACK/NACK signal with respect to the PDSCHstransmitted through SCCs, 1 to 4 resources are required to be designatedas an ARI table.

One ACK/NACK transmission resource may be required, for example, when aPDSCH including one transport block is transmitted through an SCC.

Two ACK/NACK transmission resources may be required, for example, whenPDSCHs including two transport blocks are transmitted through an SCC, orwhen a PDSCH including one transport block is transmitted through twoSCCs, respectively,

Three ACK/NACK transmission resources may be required, for example, whena PDSCH including one transport block is transmitted through one SCC andPDSCH and a PDSCH including two transport blocks is transmitted throughdifferent SCCs, or when a PDSCH including one transport block istransmitted through three SCCs, respectively.

Four ACK/NACK transmission resources may be required, for example, whena PDSCH including two transport blocks is transmitted through two SCCs,respectively, when a PDSCH including two transport blocks through oneSCC and a PDSCH including one transport block is transmitted through twodifferent SCCs, or when a PDSCH including one transport block istransmitted through four SCCs, respectively.

The ACK/NACK transmission resources with respect to a PDSCH indicated bythe PDCCH transmitted through the PCC are allocated according to animplicit resource allocation scheme, so transmission resource may not beallocated explicitly through an ARI.

Each case according to the number of ACK/NACK transmission resourcesrequired for transmitting an ACK/NACK signal with respect to the PDSCHstransmitted through SCCs will be described.

(1) When One ACK/NACK Transmission Resource is Required

Since one ACK/NACK transmission resource is required, respectiveresource sets for configuring an ARI resource mapping table haveelements corresponding to one ACK/NACK transmission resource,respectively.

For example, when resource sets transferred in advance through higherlayer signaling are {n1}, {n2}, {n3}, and {n4}, the ARI resource mappingtable may be configured as shown in Table 3 below.

TABLE 3 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resource set, i.e., {n1} 01 Second resource set, i.e.,{n2} 10 Third resource set, i.e., {n3} 11 Fourth resource set, i.e.,{n4}

Table 3 is an ARI resource mapping table configured for the sake ofconvenience in order to easily explain the present invention, and thespecific values in the ARI resource mapping table according to anembodiment of the present invention are not limited thereto. Forexample, a table may not be configured with the sets having one elementbut a table may be configured with respective elements of one set {n1,n2, n3, n4}.

Here, a 2-bit TPC on the PDCCHs with respect to the PDSCHs of the SCCs,among a plurality of CCs transmitted to downlink, may be used for theARI. The ACK/NACK transmission resource is allocated according to theARI value on the PDCCHs with respect to the PDSCHs of the received SCCs.For example, when the ARI is ‘00’, a resource set {n1} is allocated.

(2) When Two ACK/NACK transmission Resources are Required

Since two ACK/NACK transmission resources are required, respectiveresource sets for configuring an ARI resource mapping table may be foursets having elements corresponding to two ACK/NACK transmissionresources or two sets having elements corresponding to four ACK/NACKtransmission resources.

When resource sets previously transferred through higher layer signalingare four sets, e.g., {n1, n2}, {n3, n4}, {n5, n6}, {n7, n8}, havingelements corresponding to two ACK/NACK transmission resources, the ARIresource mapping table may be configured as shown in Table 4 below.

TABLE 4 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resource set, i.e., {n1, n2} 01 Second resource set,i.e., {n3, n4} 10 Third resource set, i.e., {n5, n6} 11 Fourth resourceset, i.e., {n7, n8}

When resource sets previously transferred through higher layer signalingare two sets, e.g., {n1, n2, n3, n4}, {n5, n6, n7, n8}, having elementscorresponding to four ACK/NACK transmission resources, the ARI resourcemapping table may also be configured as shown in Table 5 below.

TABLE 5 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resource set, i.e., {n1, n5} 01 Second resource set,i.e., {n2, n6} 10 Third resource set, i.e., {n3, n7} 11 Fourth resourceset, i.e., {n4, n8}

Table 4 and Table 5 are ARI resource mapping tables configured for thesake of convenience to easily explain the present invention, and thespecific values in the ARI resource mapping table according to anembodiment of the present invention are not limited thereto.

When the ARI is ‘00’, a resource set {n1, n2} is allocated in theexample of Table 4. Also, when the ARI is ‘00’, a resource set {n1, n5}is allocated in the example of Table 5.

(3) When Three ACK/NACK Transmission Resources are Required

Since three ACK/NACK transmission resources are required, respectiveresource sets for configuring an ARI resource mapping table may be foursets having elements corresponding to three ACK/NACK transmissionresources or three sets having elements corresponding to four ACK/NACKtransmission resources.

When resource sets previously transferred through higher layer signalingare four sets, e.g., {n1, n2, n3}, {n4, n5, n6}, {n7, n8, n9}, {n10,n11, n12}, having elements corresponding to three ACK/NACK transmissionresources, the ARI resource mapping table may be configured as shown inTable 6 below.

TABLE 6 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resource set, i.e., {n1, n2, n3} 01 Second resourceset, i.e., {n4, n5, n6} 10 Third resource set, i.e., {n7, n8, n9} 11Fourth resource set, i.e., {n10, n11, n12}

When resource sets previously transferred through higher layer signalingare three sets, e.g., {n1, n2, n3, n4}, {n5, n6, n7, n8}, {n9, n10, n11,n12}, having elements corresponding to four ACK/NACK transmissionresources, the ARI resource mapping table may also be configured asshown in Table 7 below.

TABLE 7 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resources of each set, i.e., {n1, n5, n9} 01 Secondresources of each set, i.e., {n2, n6, n10} 10 Third resources of eachset, i.e., {n3, n7, n11} 11 Fourth resources of each set, i.e., {n4, n8,n12}

Table 6 and Table 7 are ARI resource mapping tables configured for thesake of convenience to easily explain the present invention, and thespecific values in the ARI resource mapping table according to anembodiment of the present invention are not limited thereto.

When the ARI is ‘00’, a resource set {n1, n2, n3} is allocated in theexample of Table 6. Also, when the ARI is ‘00’, a resource set {n1, n5,n9} is allocated in the example of Table 7.

(4) When Four ACK/NACK Transmission Resources are Required

Since four ACK/NACK transmission resources are required, respectiveresource sets for configuring an ARI resource mapping table may be foursets having elements corresponding to four ACK/NACK transmissionresources.

When resource sets previously transferred through higher layer signalingare four sets, e.g., {n1, n2, n3, n4}, {n5, n6, n7, n8}, {n9, n10, n11,n12}, {n13, n14, n15, n16}, having elements corresponding to fourACK/NACK transmission resources, the ARI resource mapping table may beconfigured as shown in Table 8 below.

TABLE 8 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resource set, i.e., {n1, n2, n3, n4} 01 Secondresource set, i.e., {n5, n6, n7, n8} 10 Third resource set, i.e., {n9,n10, n11, n12} 11 Fourth resource set, i.e., {n13, n14, n15, n16}

When resource sets previously transferred through higher layer signalingare {n1, n2, n3, n4}, {n5, n6, n7, n8}, {n9, n10, n11, n12}, {n13, n14,n15, n16}, the ARI resource mapping table may also be configured asshown in Table 9 below.

TABLE 9 ACK/NACK resource indicator Mapped ACK/NACK transmissionresource 00 First resources of each set, i.e., {n1, n5, n9, n13} 01Second resources of each set, i.e., {n2, n6, n10, n14} 10 Thirdresources of each set, i.e., {n3, n7, n11, n15} 11 Fourth resources ofeach set, i.e., {n4, n8, n12, n16}

Table 8 and Table 9 are ARI resource mapping tables configured for thesake of convenience to easily explain the present invention, and thespecific values in the ARI resource mapping table according to anembodiment of the present invention are not limited thereto.

When the ARI is ‘00’, a resource set {n1, n2, n3, n4} is allocated inthe example of Table 8. Also, when the ARI is ‘00’, a resource set {n1,n5, n9, n13} is allocated in the example of Table 9.

Meanwhile, as described above, in the CA environment, HARQ ACK/NACKinformation having less than 4 bits may be transmitted according toPUCCH format 1b using channel selection.

The format of the channel selection table is previously transferred tothe UE and the BS through higher layer signaling.

The UE may be allocated ACK/NACK transmission resource for configuring achannel selection table according to a implicit resource allocationscheme or according to an explicit resource allocation scheme.

In the multi-CC system, an ACK/NACK transmission resource with respectto the PDSCH indicated by the PDCCH transmitted through a PCC may beallocated according to the implicit resource allocation scheme. AnACK/NACK transmission resource with respect to a PDSCH indicated by thePDCCH transmitted through an SCC may be allocated according to theexplicit or implicit resource allocation scheme. Here, as the explicitresource allocation scheme in which the ACK/NACK transmission resourcewith respect to the PDSCH indicated by the PDCCH transmitted through anSCC is allocated, the foregoing resource allocation scheme using the ARImay be used.

FIG. 5 is a flow chart illustrating the process of a method fortransmitting an ACK/NACK signal by the UE in a multi-antenna system.

The UE receives a plurality of CCs from the BS and receives informationon the PDCCH and the PDSCH (S1310).

Transmission resource may be allocated to the PDSCH indicated by thePDCCH transmitted through a PCC among the received CCs according to theimplicit resource allocation scheme. The UE may obtain a resource index(n_(PUCCH,0)) for allocation of the ACK/NACK resource on the PUCCHthrough an indicator of a first CCE among CCEs on the PDCCH receivedthrough the PCC. Also, the UE may obtain an additional resource indexaccording to the implicit resource allocation scheme. For example, theUE may select any one of the remaining CCEs, excluding the first CCE,among the CCEs on the received PDCCH and obtain an additional resourceindex (n_(PUCCH,1)) from the index of the corresponding CCE.

An ARI (ACK/NACK Resource Indicator) for allocating an ACK/NACKtransmission resource is transferred on the PDCCH transmitted throughthe SCC among the received CCs. As described above, 2 bits allocated tothe repeatedly transferred TPC (Transmission Power Control) with respectto the PUCCH may be used for the ARI. The UE may be allocated ACK/NACKtransmission resource explicitly through the ARI.

The UE configures a signal transmission table with the resourcesallocated according to the implicit/explicit resource allocation schemes(S1330).

As described above, the channel selection table is differentlyconfigured according to the M value (the number of bits used to transmitan ACK/NACK signal), and the number of resource indexes for configuringthe channel selection table differs according to the M value. Forexample, when the number of indexes of the ACK/NACK transmissionresources for configuring the channel selection table is 2, one ACK/NACKtransmission resource, which is related to the PDSCH indicated by thePDCCH of a PCC, may be allocated according to the implicit resourceallocation scheme and the other remaining ACK/NACK transmissionresource, which is related to the PDSCH indicated by the PDCCH of anSSC, may be allocated according the explicit resource allocation schemeby using the ARI.

The UE allocates the ACK/NACK transmission resources in the channelselection table to a first antenna (S1340). The UE allocates atransmission resource, rather than the ACK/NACK transmission resource inthe channel selection table, to a second antenna according to theexplicit resource allocation scheme (S1350). Accordingly, thetransmission resources of the first and second antennas can be preventedfrom colliding.

The UE transmits the ACK/NACK signal to the first and second antennas byusing the allocated ACK/NACK transmission resource (S1360).

Here, the multiple antenna transmission using two antennas is described,but the present invention is not limited thereto and may be applicableto a multiple antenna transmission using two or more antennas.

Table 10 shows an example of a channel selection table in case of M=2.

TABLE 10 b(0), HARQ-ACK(0), HARQ-ACK(1) n⁽¹⁾ _(PUCCH) b(1) ACK, ACK n⁽¹⁾_(PUCCH, 1) 1, 1 ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 0) 0, 1 NACK/DTX, ACK n⁽¹⁾_(PUCCH, 1) 0, 0 NACK/DTX, NACK n⁽¹⁾ _(PUCCH, 1) 1, 0 NACK, DTX n⁽¹⁾_(PUCCH, 0) 1, 0 DTX, DTX N/A N/A

Table 11 shows an example of a channel selection table in case of M=3.

TABLE 11 HARQ-ACK(0), HARQ-ACK(1), b(0), HARQ-ACK(2) n⁽¹⁾ _(PUCCH) b(1)ACK, ACK, ACK n⁽¹⁾ _(PUCCH, 2) 1, 1 ACK, ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 1)1, 1 ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH, 0) 1, 1 ACK, NACK/DTX, NACK/DTXn⁽¹⁾ _(PUCCH, 0) 0, 1 NACK/DTX, ACK, ACK n⁽¹⁾ _(PUCCH, 2) 1, 0 NACK/DTX,ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 1) 0, 0 NACK/DTX, NACK/DTX, ACK n⁽¹⁾_(PUCCH, 2) 0, 0 DTX, DTX, NACK n⁽¹⁾ _(PUCCH, 2) 0, 1 DTX, NACK,NACK/DTX n⁽¹⁾ _(PUCCH, 1) 1, 0 NACK, NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH, 0)1, 0 DTX, DTX, DTX N/A N/A

Table 12 shows an example of a channel selection table in case of M=4.

TABLE 12 HARQ-ACK(0), HARQ-ACK(1), b(0), HARQ-ACK(2), HARQ-ACK(3) n⁽¹⁾_(PUCCH) b(1) ACK, ACK, ACK, ACK n⁽¹⁾ _(PUCCH, 1) 1, 1 ACK, ACK, ACK,NACK/DTX n⁽¹⁾ _(PUCCH, 1) 1, 0 NACK/DTX, NACK/DTX, NACK, DTX n⁽¹⁾_(PUCCH, 2) 1, 1 ACK, ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH, 1) 1, 0 NACK,DTX, DTX, DTX n⁽¹⁾ _(PUCCH, 0) 1, 0 ACK, ACK, NACK/DTX, NACK/DTX n⁽¹⁾_(PUCCH, 1) 1, 0 ACK, NACK/DTX, ACK, ACK n⁽¹⁾ _(PUCCH, 3) 0, 1 NACK/DTX,NACK/DTX, NACK/DTX, NACK n⁽¹⁾ _(PUCCH, 3) 1, 1 ACK, NACK/DTX, ACK,NACK/DTX n⁽¹⁾ _(PUCCH, 2) 0, 1 ACK, NACK/DTX, NACK/DTX, ACK n⁽¹⁾_(PUCCH, 0) 0, 1 ACK, NACK/DTX, NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH, 0) 1, 1NACK/DTX, ACK, ACK, ACK n⁽¹⁾ _(PUCCH, 3) 0, 1 NACK/DTX, NACK, DTX, DTXn⁽¹⁾ _(PUCCH, 1) 0, 0 NACK/DTX, ACK, ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 2) 1, 0NACK/DTX, ACK, NACK/DTX, ACK n⁽¹⁾ _(PUCCH, 3) 1, 0 NACK/DTX, ACK,NACK/DTX, NACK/DTX n⁽¹⁾ _(PUCCH, 1) 0, 1 NACK/DTX, NACK/DTX, ACK, ACKn⁽¹⁾ _(PUCCH, 3) 0, 1 NACK/DTX, NACK/DTX, ACK, NACK/DTX n⁽¹⁾ _(PUCCH, 2)0, 0 NACK/DTX, NACK/DTX, NACK/DTX, ACK n⁽¹⁾ _(PUCCH, 3) 0, 0 DTX, DTX,DTX, DTX N/A N/A

Here, HARQ-ACK(0)˜HARQ-ACK(3) are ACK/NACK types with respect totransport blocks to be determined whether or not they have been normallyreceived (decoded).

n⁽¹⁾ _(PUCCH) is an ACK/NACK transmission resource to be used fortransmission. Here, the respective transmission resources, e.g., {n⁽¹⁾_(PUCCH,0),n⁽¹⁾ _(PUCCH,1)} in case of M=2, {n⁽¹⁾ _(PUCCH,0)n⁽¹⁾_(PUCCH,1),n⁽¹⁾ _(PUCCH,2)} in case of M=3, and {n⁽¹⁾ _(PUCCH,0),n⁽¹⁾_(PUCCH,1),n⁽¹⁾ _(PUCCH,2), n⁽¹⁾ _(PUCCH,3)} in case of M=4,constituting the channel selection are the transmission resource,related to the PDSCH indicated by the PDCCH of the PCC, which has beenallocated according to the implicit resource allocation scheme and thetransmission resource, related to the PDSCH indicated by the PDCCH ofthe SCC, which has been allocated according to the explicit resourceallocation.

b(0)b(1) is a QPSK symbol of an ACK/NACK signal to be transmitted. Whenthe value of b(0),b(1) is mapped to N/A, namely, in case of DTX(Discontinuous Transmission), since it corresponds to, for example, acase in which the UE has not received the PDCCH, so the UE does nottransmit an ACK/NACK in a subframe n.

As described above, when the UE allocates resource to the first antenna,by using the signal transmission table, e.g., the channel selectiontable, the UE transmits the corresponding transmission symbols (b(0),b(1)) on the PUCCH by using the ACK/NACK transmission resource (n⁽¹⁾_(PUCCH)) mapped according to an ACK/NACK type corresponding to thedecoding results of the received PDSCHs. For example, in case of M=3,when the types of ACK/NACK signals to be transmitted are all ACK, the UEtransmits the value (1, 1) of the corresponding symbols (b(0), b(1)) onthe PUCCH by using the ACK/NACK transmission resource n⁽¹⁾ _(PUCCH,2).

The foregoing channel selection table is an example for explaining thetechnical concept of the present invention, so the present invention isnot limited thereto and may be configured in various manners within thescope of the technical concept of the present invention.

FIG. 6 is a schematic block diagram showing an example of an apparatusfor transmitting an HARQ ACK/NACK signal in the multi-antenna system.FIG. 6 illustrates multi-antenna transmission using two antennas, butthe present invention is not limited thereto, and the present inventionmay also be applicable to a multi-antenna transmission using two or moreantennas. Also, for the sake of brevity, some of a configuration such asan encoder, a mapper, a multiplexing unit, and the like, will be omittedin the following description.

A symbol modulation unit 1410 modulates an ACK/NACK signal and outputsmodulation symbols. A resource determining unit 1420 allocates ACK/NACKresource to be used for transmitting the ACK/NACK modulation symbols toa first antenna 1440 a and a second antenna 1440 b. The results ofresource allocation are transmitted, for example, in the form of aresource index, or the like, to first and second spreading units 1430 aand 1430 b.

The first resource spreading unit 1430 a spreads ACK/NACK modulationsymbols according to the resource allocation results of the resourcedetermining unit 1420 with respect to the first antenna 1440 a andtransmits the same through the second antenna 1440 b.

When the ACK/NACK signal is transmitted by using multiple antennas,since the same ACK/NACK symbols are transmitted by using differentresources through the different antennas, diversity can be obtained.

As described above, the ACK/NACK transmission resource is allocated withrespect to the first antenna according to a channel selection table anddifferent resource not mapped in the channel selection table isallocated with respect to the second antenna, and the same ACK/NACKsignal is transmitted, whereby a collision of resources is prevented andtransmission diversity is obtained.

FIG. 7 is a schematic block diagram of a wireless communication systemimplemented by an embodiment of the present invention.

A BS 1510 includes a signal processing unit 1511, a memory 1512, and anRF unit 1513.

The signal processing unit 1511 implements the proposed functions,procedures and/or methods. The signal processing unit 1511 may configurea downlink physical channel and perform HARQ. Also, the signalprocessing unit 1511 may include resource indexes constituting a channelselection table for a resource allocation of an ACK/NACK signal in adownlink transport block or process an ARI, or the like, explicitlyindicating the resource indexes. In this case, signal processing isprocessing in a broad sense including a signal creation, modulation,allocation of signal content, determining of a signal transmission, andthe like. For example, how many resource indexes among the resourceindexes constituting the channel selection table for an ACK/NACKresource allocation are to be allocated according to an explicitresource allocation scheme, how many resource indexes among the resourceindexes constituting the channel selection table are to be allocatedaccording to an implicit resource allocation scheme, which resources areto be based on in order to be allocated resource indexes according tothe implicit resource allocation scheme, and the like, may be determinedby the signal processing unit 1511 and transmitted to a UE 1520. Also,when a plurality of component carriers are transmitted, the signalprocessing unit 1511 may transmit an ARI for allocating ACK/NACKtransmission resource by using bits allocated to a repeated TPC withrespect to the same PUCCH.

The memory 1512, connected to the signal processing unit 1511, storesprotocols or parameters for an HARQ operation. Also, the memory 1512 maystore the channel selection table and/or the ARI mapping table. Theformats of the channel selection table and/or the ARI mapping table arepreviously determined by a higher layer, so the same formats of channelselection table and/or the ARI mapping table exist in the UE and the BS.The BS 1510 may use the channel selection table and/or the ARI mappingtable stored in the memory 1512 in order to process an ACK/NACK signaltransmitted from the UE 1520.

The RF unit 1513, connected to the signal processing unit 1511,transmits and/or receives a radio signal, and may include a plurality ofantennas.

The UE 1520 may include a signal processing unit 1521, a memory 1522,and an RF unit 1523.

The signal processing unit 1521 implements the proposed functions,procedures and/or methods. The signal processing unit 1521 may obtain aplurality of resources and transmit an HARQ ACK/NACK signal throughmultiple antennas by using the plurality of resources. Also, the signalprocessing unit 1521 may also serve to modulate symbols and spread themodulation symbols for an ACK/NACK signal transmission. Also, the signalprocessing unit 1521 may allocate transmission resource according to animplicit or explicit resource allocation scheme through a radio signalreceived from the BS. Also, the signal processing unit 1521 may allocatean ACK/NACK transmission resource by using a channel selection tableand/or an ARI mapping table and process an ACK/NACK signal.

The memory 1522, connected to the signal processing unit 1521, may storeprotocols or parameter for an HARQ operation and the same channelselection table and/or ARI mapping table as that of the BS 1510. The RFunit 1523, connected to the signal processing unit 1521, may transmitand/or receive a radio signal, and may include a plurality of antennas.

The signal processing units 1511 and 1521 may include an ASIC(Application-Specific Integrated Circuit), a chip-set, a logical circuitand/or a data processor. The memories 1512 and 1522 may include a ROM(Read-Only Memory), a RAM (Random Access Memory), a flash memory, amemory card, a storage medium, and/or any other storage devices. The RFunits 1513 and 1523 may include a baseband circuit for processing aradio signal. When the embodiments are implemented by software, theforegoing techniques may be implemented by modules (processes,functions, or the like) performing the foregoing functions. The modulesmay be stored in the memories 1512 and 1522 and executed by the signalprocessing units 1511 and 1521. The memories 1512 and 1522 may beprovided within or outside signal processing units 1511 and 1512,respectively, or may be connected to the signal processing units 1511and 1521 through a well-known unit, respectively.

Control information transferred from a higher layer described in thepresent disclosure may also be transmitted via a physical controlchannel, and may be periodically or aperiodically updated according to arequest from a BS or a UE or according to a predetermined certain ruleor instruction.

In the exemplary system as described above, the methods are describedbased on the flow chart by sequential steps or blocks, but the presentinvention is not limited to the order of the steps, and a step may beperformed in different order from another step as described above orsimultaneously performed. It would be understood by a skilled person inthe art that the steps are not exclusive, a different step may beincluded, or one or more of the steps of the flow chart may be deletedwithout affecting the scope of the present invention.

The preferred embodiments of the present invention have been describedwith reference to the accompanying drawings, and it will be apparent tothose skilled in the art that various modifications and variations canbe made in the present invention without departing from the scope of theinvention. Thus, the technical idea of the present invention should beinterpreted to embrace all such alterations, modifications, andvariations in addition to the accompanying drawings.

What is claimed is:
 1. A method for transmitting a Hybrid AutomaticRepeat reQuest (HARQ) Acknowledgement (ACK) by a user equipment (UE),the method comprising: receiving an indication of first and second HARQACK resource sets through a higher layer signaling, the first HARQ ACKresource set including one or more first HARQ ACK resources and thesecond HARQ ACK resource set including one or more second HARQ ACKresources; and receiving downlink control information (DCI) including atransmission power control (TPC) field, the DCI indicating a downlinkdata transmission, wherein when the downlink data transmission is forone transport block, the TPC field is configured to be used to indicatea single HARQ ACK resource which is included in the first HARQ ACKresource set, and wherein when the downlink data transmission is for twotransport blocks, the TPC field is configured to be used to indicate twoHARQ ACK resources each of which is included in the first HARQ ACKresource set and the second HARQ ACK resource set, respectively;mapping, based on a channel selection, an HARQ ACK associated with thedownlink data transmission onto a combination of a selected HARQ ACKresource obtained from the single HARQ ACK resource or the two HARQ ACKresources and a modulation symbol; and transmitting the HARQ ACK byusing the combination, wherein the HARQ ACK resources are associatedwith a physical uplink control channel (PUCCH), and wherein the DCI isincluded in a physical downlink control channel (PDCCH).
 2. The methodof claim 1, wherein when a value of the TPC field is ‘00’, the TPC fieldindicates at least one of a first one of the one or more first HARQ ACKresources in the first HARQ ACK resource set or a first one of the oneor more second HARQ ACK resources in the second HARQ ACK resource set;when the value of the TPC field is ‘01’, the TPC field indicates atleast one of a second one of the one or more first HARQ ACK resources inthe first HARQ ACK resource set or a second one of the one or moresecond HARQ ACK resources in the second HARQ ACK resource set; when thevalue of the TPC field is ‘10’, the TPC field indicates at least one ofa third one of the one or more first HARQ ACK resources in the firstHARQ ACK resource set or a third one of the one or more second HARQ ACKresources in the second HARQ ACK resource set; and when the value of theTPC field is ‘11’, the TPC field indicates at least one of a fourth oneof the one or more first HARQ ACK resources in the first HARQ ACKresource set or a fourth one of the one or more second HARQ ACKresources in the second HARQ ACK resource set, respectively.
 3. Themethod of claim 1, wherein both of the first HARQ ACK resource set andthe second HARQ ACK resource set include four HARQ ACK resources whichare configured by a radio resource control signaling.
 4. A userequipment (UE) to transmit a Hybrid Automatic Repeat reQuest (HARQ)Acknowledgement (ACK), the UE comprising: a processor; and atransceiver, wherein the processor is configured to: receive, via thetransceiver, an indication of first and second HARQ ACK resource setsthrough a higher layer signaling, the first HARQ ACK resource setincluding one or more first HARQ ACK resources and the second HARQ ACKresource set including one or more second HARQ ACK resources; andreceive, via the transceiver, downlink control information (DCI)including a transmission power control (TPC) field, the DCI indicating adownlink data transmission, wherein when the downlink data transmissionis for one transport block, the TPC field is configured to be used toindicate a single HARQ ACK resource which is included in the first HARQACK resource set, and wherein when the downlink data transmission is fortwo transport blocks, the TPC field is configured to be used to indicatetwo HARQ ACK resources each of which is included in the first HARQ ACKresource set and the second HARQ ACK resource set, respectively; map,based on a channel selection, an HARQ ACK associated with the downlinkdata transmission onto a combination of a selected HARQ ACK resourceobtained from the single HARQ ACK resource or the two HARQ ACK resourcesand a modulation symbol; and transmit, via the transceiver, the HARQ ACKby using the combination, wherein the HARQ ACK resources are associatedwith a physical uplink control channel (PUCCH), and wherein the DCI isincluded in a physical downlink control channel (PDCCH).
 5. The UE ofclaim 4, wherein when a value of the TPC field is ‘00’, the TPC fieldindicates at least one of a first one of the one or more first HARQ ACKresources in the first HARQ ACK resource set or a first one of the oneor more second HARQ ACK resources in the second HARQ ACK resource set;when the value of the TPC field is ‘01’, the TPC field indicates atleast one of a second one of the one or more first HARQ ACK resources inthe first HARQ ACK resource set or a second one of the one or moresecond HARQ ACK resources in the second HARQ ACK resource set; when thevalue of the TPC field is ‘10’, the TPC field indicates at least one ofa third one of the one or more first HARQ ACK resources in the firstHARQ ACK resource set or a third one of the one or more second HARQ ACKresources in the second HARQ ACK resource set; and when the value of theTPC field is ‘11’, the TPC field indicates at least one of a fourth oneof the one or more first HARQ ACK resources in the first HARQ ACKresource set or a fourth one of the one or more second HARQ ACKresources in the second HARQ ACK resource set, respectively.
 6. The UEof claim 4, wherein both of the first HARQ ACK resource set and thesecond HARQ ACK resource set include four HARQ ACK resources which areconfigured by a radio resource control signaling.
 7. A method forreceiving a Hybrid Automatic Repeat reQuest (HARQ) Acknowledgement (ACK)from a user equipment (UE), the method comprising: transmitting anindication of first and second HARQ ACK resource sets through a higherlayer signaling, the first HARQ ACK resource set including one or morefirst HARQ ACK resources and the second HARQ ACK resource set includingone or more second HARQ ACK resources; and transmitting downlink controlinformation (DCI) including a transmission power control (TPC) field,the DCI indicating a downlink data transmission, wherein when thedownlink data transmission is for one transport block, the TPC field isconfigured to be used to indicate a single HARQ ACK resource which isincluded in the first HARQ ACK resource set, and wherein when thedownlink data transmission is for two transport blocks, the TPC field isconfigured to be used to indicate two HARQ ACK resources each of whichis included in the first HARQ ACK resource set and the second HARQ ACKresource set, respectively, wherein an HARQ ACK associated with thedownlink data transmission is mapped, based on a channel selection, ontoa combination of a selected HARQ ACK resource obtained from the singleHARQ ACK resource or the two HARQ ACK resources and a modulation symbol,and the HARQ ACK is received by using the combination, and wherein theHARQ ACK resources are associated with a physical uplink control channel(PUCCH), and wherein the DCI is included in a physical downlink controlchannel (PDCCH).
 8. The method of claim 7, wherein when a value of theTPC field is ‘00’, the TPC field indicates at least one of a first oneof the one or more first HARQ ACK resources in the first HARQ ACKresource set or a first one of the one or more second HARQ ACK resourcesin the second HARQ ACK resource set; when the value of the TPC field is‘01’, the TPC field indicates at least one of a second one of the one ormore first HARQ ACK resources in the first HARQ ACK resource set or asecond one of the one or more second HARQ ACK resource values in thesecond HARQ ACK resource set; when the value of the TPC field is ‘10’,the TPC field indicates at least one of a third one of the one or morefirst HARQ ACK resources in the first HARQ ACK resource set or a thirdone of the one or more second HARQ ACK resources in the second HARQ ACKresource set; and when the value of the TPC field is ‘11’, the TPC fieldindicates at least one of a fourth one of the one or more first HARQ ACKresources in the first HARQ ACK resource set or a fourth one of the oneor more second HARQ ACK resources in the second HARQ ACK resource set,respectively.
 9. The method of claim 7, wherein both of the first HARQACK resource set and the second HARQ ACK resource set include four HARQACK resources which are configured by a radio resource controlsignaling.
 10. A base station to receive a Hybrid Automatic RepeatreQuest (HARQ) Acknowledgement (ACK), the base station comprising: aprocessor; and a transceiver, wherein the processor is configured to:transmit, via the transceiver, to a user equipment (UE) an indication offirst and second HARQ ACK resource sets through a higher layersignaling, the first HARQ ACK resource set including one or more firstHARQ ACK resources and the second HARQ ACK resource set including one ormore second HARQ ACK resources; and transmit, via the transceiver, tothe UE downlink control information (DCI) including a transmission powercontrol (TPC) field, the DCI indicating a downlink data transmission,wherein when the downlink data transmission is for one transport block,the TPC field is configured to be used to indicate a single HARQ ACKresource which is included in the first HARQ ACK resource set, andwherein when the downlink data transmission is for two transport blocks,the TPC field is configured to be used to indicate two HARQ ACKresources each of which is included in the first HARQ ACK resource setand the second HARQ ACK resource set, respectively, wherein an HARQ ACKassociated with the downlink data transmission is mapped, based on achannel selection, onto a combination of a selected HARQ ACK resourceobtained from the single HARQ ACK resource or the two HARQ ACK resourcesand a modulation symbol, and the HARQ ACK is received by using thecombination, and wherein of the HARQ ACK resources are associated with aphysical uplink control channel (PUCCH), and wherein the DCI is includedin a physical downlink control channel (PDCCH).
 11. The base station ofclaim 10, wherein when a value of the TPC field is ‘00’, the TPC fieldindicates at least one of a first one of the one or more first HARQ ACKresources in the first HARQ ACK resource set or a first one of the oneor more second HARQ ACK resources in the second HARQ ACK resource set;when the value of the TPC field is ‘01’, the TPC field indicates atleast one of a second one of the one or more first HARQ ACK resources inthe first HARQ ACK resource set or a second one of the one or moresecond HARQ ACK resource values in the second HARQ ACK resource set;when the value of the TPC field is ‘10’ the TPC field indicates at leastone of a third one of the one or more first HARQ ACK resources in thefirst HARQ ACK resource set or a third one of the one or more secondHARQ ACK resources in the second HARQ ACK resource set; and when thevalue of the TPC field is ‘11’ the TPC field indicates at least one of afourth one of the one or more first HARQ ACK resources in the first HARQACK resource set or a fourth one of the one or more second HARQ ACKresources in the second HARQ ACK resource set, respectively.
 12. Thebase station of claim 10, wherein both of the first HARQ ACK resourceset and the second HARQ ACK resource set include four HARQ ACK resourceswhich are configured by a radio resource control signaling.